Hi Stephen,
Thanks for the quick review!
On 10/03/2013 10:25 PM, Stephen Boyd wrote:
> On 10/03/13 07:52, Stanimir Varbanov wrote:
>> +#define PRNG_CONFIG_MASK 0x00000002
>> +#define PRNG_CONFIG_HW_ENABLE BIT(1)
>
> These two are the same so please drop the PRNG_CONFIG_MASK define and
> just use the PRNG_CONFIG_HW_ENABLE define.
>
OK I will drop the mask and rework the code related to it.
>> +#define PRNG_STATUS_DATA_AVAIL BIT(0)
>> +
>> +#define MAX_HW_FIFO_DEPTH 16
>> +#define MAX_HW_FIFO_SIZE (MAX_HW_FIFO_DEPTH * 4)
>> +#define WORD_SZ 4
>> +
>> +struct msm_rng {
>> + void __iomem *base;
>> + struct clk *clk;
>> +};
>> +
>> +static int msm_rng_enable(struct msm_rng *rng, int enable)
>> +{
>> + u32 val;
>> + int ret;
>> +
>> + ret = clk_prepare_enable(rng->clk);
>> + if (ret)
>> + return ret;
>> +
>> + if (enable) {
>> + /* Enable PRNG only if it is not already enabled */
>> + val = readl_relaxed(rng->base + PRNG_CONFIG);
>> + if (val & PRNG_CONFIG_HW_ENABLE)
>> + goto already_enabled;
>> +
>> + /* PRNG is not enabled */
>> + val = readl_relaxed(rng->base + PRNG_LFSR_CFG);
>> + val &= ~PRNG_LFSR_CFG_MASK;
>> + val |= PRNG_LFSR_CFG_CLOCKS;
>> + writel(val, rng->base + PRNG_LFSR_CFG);
>> +
>> + val = readl_relaxed(rng->base + PRNG_CONFIG);
>> + val &= ~PRNG_CONFIG_MASK;
>> + val |= PRNG_CONFIG_HW_ENABLE;
>> + writel(val, rng->base + PRNG_CONFIG);
>
> This could just be
>
> val = readl_relaxed(rng->base + PRNG_CONFIG);
> val |= PRNG_CONFIG_HW_ENABLE;
> writel(val, rng->base + PRNG_CONFIG);
>
>
>> + } else {
>> + val = readl_relaxed(rng->base + PRNG_CONFIG);
>> + val &= ~PRNG_CONFIG_MASK;
>> + writel(val, rng->base + PRNG_CONFIG);
>> + }
>> +
>> +already_enabled:
>> + clk_disable_unprepare(rng->clk);
>> + return 0;
>> +}
>> +
> [...]
>> +static int msm_rng_probe(struct platform_device *pdev)
>> +{
>> + struct msm_rng *rng;
>> + struct device_node *np;
>> + struct resource res;
>> + int ret;
>> +
>> + np = of_node_get(pdev->dev.of_node);
>> + if (!np)
>> + return -ENODEV;
>
> This is unnecessary.
I used this call because CONFIG_OF_DYNAMIC could be enabled at some
time. Isn't that possible? I saw that of_node_get|put is used in .probe
on few places in drivers.
>
>> +
>> + rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
>> + if (!rng) {
>> + ret = -ENOMEM;
>> + goto err_exit;
>> + }
>> +
>> + ret = of_address_to_resource(np, 0, &res);
>> + if (ret)
>> + goto err_exit;
>
> We should just do
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> rng->base = devm_ioremap_resource(&pdev->dev, res);
> if (IS_ERR(rng->base))
> return PTR_ERR(rng->base);
>
>> +
>> + rng->base = devm_ioremap_resource(&pdev->dev, &res);
>> + if (IS_ERR(rng->base)) {
>> + ret = PTR_ERR(rng->base);
>> + goto err_exit;
>> + }
>> +
>> + rng->clk = devm_clk_get(&pdev->dev, "prng");
>> + if (IS_ERR(rng->clk)) {
>> + ret = PTR_ERR(rng->clk);
>> + goto err_exit;
>> + }
>> +
>> + msm_rng_ops.priv = (unsigned long) rng;
>> + ret = hwrng_register(&msm_rng_ops);
>> + if (ret)
>> + dev_err(&pdev->dev, "failed to register hwrng\n");
>> +
>> +err_exit:
>
> Doing all that should make this goto exit path unnecessary.
>
>> + of_node_put(np);
>> + return ret;
>> +}
>> +
>> +static int msm_rng_remove(struct platform_device *pdev)
>> +{
>> + hwrng_unregister(&msm_rng_ops);
>> + return 0;
>> +}
>> +
>> +static struct of_device_id msm_rng_of_match[] = {
>
> const?
>
>> + { .compatible = "qcom,prng", },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(of, msm_rng_of_match);
>> +
>> +static struct platform_driver msm_rng_driver = {
>> + .probe = msm_rng_probe,
>> + .remove = msm_rng_remove,
>> + .driver = {
>> + .name = KBUILD_MODNAME,
>> + .owner = THIS_MODULE,
>> + .of_match_table = of_match_ptr(msm_rng_of_match),
>> + }
>> +};
>> +module_platform_driver(msm_rng_driver);
>> +
>> +MODULE_AUTHOR("The Linux Foundation");
>> +MODULE_DESCRIPTION("Qualcomm MSM random number generator driver");
>> +MODULE_LICENSE("GPL v2");
>
>
regards,
Stan
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